1. Field of the Invention
The instant invention relates to a stereo image display technique, by which a 3D image display may produce a stereoscopic image that takes viewpoint into account. By taking viewpoint into account, a stereoscopic image may be created which appears to remain at approximately the same location in space as viewpoint changes.
2. Description of Related Art
Methods of implementing a 3D stereoscopic image are described as follows:
First of all, as mentioned in the following description, in order to implement a 3D stereoscopic image, a first image for a left eye and a second image for a right eye need to arrive at both eyes in a manner of being discriminated from each other. For this, various methods are explained as follows. These images shall be referred to as first or left image and second or right image.
Prior art displays which may be viewed as 3D images generally fall into four methods for display of 3D imagery.
The first method employs polarized light images where the planes for first and second images are rotated by approximately 90 degrees. A similar method employs first and second circularly or elliptically polarized images. These polarized first and second images pass through polarized spectacles so that the corresponding image reaches the first or left and second or right eye.
Another similar method employs liquid crystal shutter spectacles which open and close left and right shutters so as to allow the corresponding image to reach the correct eye. Prior art employing liquid crystal shutters do not account for a change in viewing location from one viewer to the next. Therefore a 3D image would appear to be at different locations in space when viewed from differing viewpoints. Thus if one viewer pointed at a 3D stereoscopic object, a viewer at a second viewing location would have difficulty determining what is being pointed at.
A third method employs a lenticular screen provided between a display and both eyes. In particular, a propagating direction of light is refracted via lens on the lenticular screen, whereby different images arrive at both eyes, respectively.
A fourth method requires no spectacles and utilizes parallax barriers so that each eye sees the proper image. This technology shall be referred to as auto stereoscopic.
A final method employs differently colored filtered images, which are viewed through glasses whose lenses are colored differently. This method or system shall be referred to as anaglyphic or an anaglyph.